Nicotinic acid, also known as niacin or vitamin B3, is an essential nutrient that plays a crucial role in various physiological processes. It is involved in the metabolism of carbohydrates, fats, and proteins, and it is essential for the production of energy in the body. Niacin also helps maintain healthy skin, nervous system function, and digestive system function. Additionally, it is known for its role in supporting cardiovascular health by helping to manage cholesterol levels. Niacin can be obtained from a variety of foods and is also available as a dietary supplement.